Questions of the Geology of Kuzbass, 2

Proceedings of the Tomsk Order of the Red Banner of Labor Polytechnic Institute named after S. M. Kirov, vol. 99, 1959

On the Use of Organic Remains for Correlating Sections from Boreholes and Exploration Lines under the Conditions of Geological Exploration Teams

(Case Study of Coal Deposits of the Erunakovskaya Formation, Kuzbass)

O. A. Betekhtina and L. L. Khalfin

General Remarks

The exploration of coal deposits belonging to the deposits of the Kolchugino Series—especially in areas lacking, or almost lacking, natural outcrops and possessing more or less complex tectonics—poses a number of difficult tasks for geological exploration teams, tasks caused by the extreme facies variability of these deposits and by the absence of marker lithological horizons.

Under these conditions, correlation of sections from boreholes, exploration lines, and areas is a rather complex matter and can be considerably facilitated and refined through the rational use of paleontological material contained in drill core. At the same time, however, it is necessary that such use of organic remains be carried out by the personnel of the teams directly in the course of exploration work. In other words, the primary processing of paleontological material and the biostratigraphic analysis of sections must be transferred directly to the teams, making the paleontological method (alongside the lithological one) a method of the teams’ everyday work.

Certain well-known difficulties stand in the way of such an introduction of the paleontological method into the everyday practice of geological teams; they are as follows.

Usually, for biostratigraphic comparison of sections, an exact species-level identification of fauna or flora is envisaged, which requires considerable time and a certain amount of experience even when good keys and reference manuals are available. The task, however, is to involve the broadest possible circle of team personnel in the primary paleontological description of core. Consequently, the task is to develop, for application to the specific working conditions of geological exploration teams, a methodology for the paleontological description of core that is accessible not only to team geologists but also to the collecting staff, and a methodology of biostratigraphic analysis that is fully applicable in the teams. Such a methodology is proposed in the present instruction. This methodology is based on an empirically established proposition: in application to the coal-bearing deposits of Kuzbass, the identification of marker biostratigraphic horizons for restric-

of a given area (deposit) is quite possible on the basis of a general characterization of the fauna and flora. The amount of paleontological knowledge required for this is minimal and does not require special training.

The general characterization of the organic remains of the Kolchuginskaya Series consists of the following elements:

1. Composition of the fauna and flora. What is taken into account is the presence in a given horizon, first, of major systematic groups: lamellibranch mollusks (pelecypods), ostracods, ferns, horsetails, cordaites. Second, a few of the most frequently occurring and readily recognizable genera are recorded; for example, among ferns—Pecopteris, Callipteris, Glottophyllum; among pelecypods—Anthraconauta, Microdontella, Palaeanodonta.

2. General character of the fauna and flora: uniform or diverse composition, large or small pelecypod shells, large or small cordaite leaves, broad or narrow horsetail stems, etc.

3. Quantitative development of the fauna and flora as a whole or of their individual components: single specimens, rare specimens, abundance or mass development.

4. State of preservation of the fauna and flora: whole shells or fragments, accumulations of broken shells (shell debris), whole or damaged leaves, fragments of leaves and pieces of stems, disorderly or, in a definite way, oriented arrangement of organic remains on bedding planes.

On the basis of paleontological material characterized according to the program outlined above and occurring in different parts of the section in each borehole, it is possible to distinguish certain marker horizons, usually traceable well within the limits of a deposit. For example, in the deposits of the Uskatskoye deposit, on the basis of features in the distribution of the fauna, four faunal horizons are distinguished, which are fairly easily differentiated from one another by the general character of the fauna and its species composition. Thus, Horizon I, occupying the lowest stratigraphic position, is characterized by a very scant, depressed-type fauna. Horizon II contains a fairly abundant fauna, but usually of small size (normal type). Highly characteristic of this horizon is the presence among the fauna of representatives of the genus Palaeanodonta Amal. This horizon with palaeanodonts is excellently traced across the strike of the deposit structure (along exploration line XII) and in 8 boreholes along the strike. The remaining three horizons are traced equally well.

In the Tagaryshskoye deposit, four faunal horizons are also distinguished. One of them (Horizon II) is characterized by a flourishing fauna (see Figs. 11, 12). The deposits of this stratigraphic interval are rich in pelecypod fauna of various species and sizes. Large shells of anthraconauts occur quite frequently. This horizon is also readily recognized by the general appearance of the fauna both along the strike (in sections along the III, IV, and Tagarysh prospective lines) and across the strike.

For the identification and tracing of such faunal and floral horizons, it is necessary that, during the primary description of core in drilling logs, organic remains be recorded and characterized. For this, in turn, it is necessary that the personnel of the parties responsible for documenting boreholes be familiar with the most important groups of fauna and flora and be able readily to recognize some of their representatives. The present instruction contains the necessary information in this field, as well as directions relating to the paleontological description of core and to the analysis of materials obtained in this way.

Fauna

In the deposits of the Erunakovskaya Formation, two groups of animals are most widespread—lamellibranch mollusks (pelecypods) and ostracods; these should be used for the general paleontological characterization of borehole sections. As for ostracods, their small shells, even for preliminary identifications, require the use of a strong hand lens or microscope. Therefore, in the process of the initial description of the core one should confine oneself to recording only their presence and abundance; it is true, however, that in some cases even the most cursory examination makes it possible to establish that in different beds or horizons there are either very small (0.3 mm) or very large (up to 2.5 mm) ostracod shells; such observations are useful to note in the drilling log.

Pelecypods, which have larger shells, are considerably more suitable for the general faunal characterization of the deposits. At present, eight different genera of pelecypods are known from the deposits of the Il’inskaya and Erunakovskaya formations. Of these, the genera Microdontella, Palaeanodonta, and Anthraconauta are the most widespread, and it is very important to distinguish them. Their brief characteristics are as follows.

Microdontella (Fig. 1): the shell is rounded in outline (isometric); the umbo is located almost in the middle of the upper margin; the surface of the valves is covered with concentric ridges and lines; the dimensions are usually small and medium (up to 1 cm across), sometimes larger (up to 2 cm).

Palaeanodonta (Fig. 2): the shell is elongated (developed lengthwise); the upper and lower margins are directed almost parallel to one another; the umbones are displaced forward from the middle of the upper margin, but are considerably removed from the anterior margin as well; the shell does not widen posteriorly; the surface of the valves is covered with concentric lines; the dimensions are often considerable (up to 4 cm), but small forms (1–1.5 cm) are also encountered more rarely.

Fig. 1. Microdontellas (genus Microdontella). Shells of rounded outline. Natural size.

Fig. 2. Various palaeanodonts (genus Palaeanodonta). Shells elongated; upper and lower margins parallel. Natural size.

Anthraconauta (Fig. 3): the shell is oblique (developed diagonally), to some degree rounded-triangular in outline; the umbones are very close to the anterior margin; the anterior end of the shell is narrow (not high), and posteriorly the shell widens greatly; the surface of the valves is covered with concentric lines.

The entire assemblage of pelecypods occurring in the Il’inskaya and Erunakovskaya formations constitutes the so-called Kolchuginsk fauna complex. This complex is divided into several faunas, differing both in composition and in general character. First, the so-called coal-bearing fauna (Chertinsky type of fauna) is distinguished; it is characterized by extreme poverty: anthraconautas and palaeanodonts are absent.

or occur as single specimens; usually the fauna consists of the same microdontellids; shell sizes are often small and even dwarf.

A flourishing fauna (the Baidaevka type of fauna) has the opposite character: the shells often form mass accumulations; along with microdontellids, anthraconautids are very numerous, not infrequently attaining large sizes (up to 3 cm).

Fig. 3. Various anthraconautids (genus Anthraconauta). Natural size. The shells are obliquely triangular, widening posteriorly.

Along with these two extreme types of fauna, it is necessary to distinguish the so-called normal fauna (the Krasulino type). This fauna is characterized by a considerable number of individuals, a varied species composition, and a rather large number of anthraconautids, but all forms, except Microdontella, are fairly small; the anthraconautids usually do not exceed 1.5 cm.

Flora

The deposits of the Ilyinskaya and Erunakovskaya formations are extremely rich in plant remains, which are present in almost every lithological variety of rock. Usually these are remains of three principal groups of plants: ferns, cordaites, and articulate-stemmed plants (horsetails). For a primary paleontological characterization of a section, it is necessary to distinguish the following principal genera.

Ferns

1. Pecopteris (Fig. 4). The leaves (fronds) of these ferns are large, compound-pinnate, and consist of separate divisions—pinnae of various orders.

Fig. 4. Ferns of the collective genus Pecopteris.

Usually in the core it is possible to observe only part of a frond—the so-called pinnae of the last order, consisting of a rachis set on both sides with small leaflets—pinnules. The pinnules are attached to the rachis by a broad base, at a more or less acute angle; the margins of the pinnules are either entire (if the pinnules are very small—up to 0.3 cm), but for the most part they have wavy, incised, and even deeply

dissected margins (Fig. 4). In each pinnule there passes a sinuous midrib; from it depart lateral veins, which fork up to two times.

2. Callipteris (Fig. 5). These ferns also have compound leaves (fronds). But the pinnules are usually larger (up to 1 cm long and more than 0.5 cm wide), entire-margined, with parallel lateral margins and a rounded apex.

Fig. 5. Ferns of the genus Callipteris.

Already by the outline of the pinnules they are very readily distinguished from representatives of the preceding genus. In addition, the venation is also sharply different. There is a midrib; from it, at a very acute angle, straight, parallel lateral veins depart on both sides.

3. Glottophyllum. This plant occurs as impressions of small leaves (Fig. 6). The leaves have an elongate-oval or broadly spatulate shape and somewhat resemble leaves of cordaites (see below). The base of the leaf is drawn out into a narrow, sometimes rather long petiole, which is never observed in leaves of cordaites. In addition, the veins in the leaves of Glottophyllum are sparse and divergent, which also sharply distinguishes them from the dense, nearly parallel veins of cordaites.

Fig. 6. Genus Glottophyllum—sparse (widely spaced) veins and a distinct petiole.

Cordaites. These plants are represented by numerous impressions of various leaves, which are present in almost every lithological variety. The leaves are sufficiently dense and therefore give good impressions even on sandstones; the veins are dense, almost parallel. In characterizing the flora it is necessary to note the following varieties of cordaite leaves:

a) large leaves, with a broad leaf blade—more than 1.5 cm wide (Fig. 8a).

b) large leaves, with a narrow leaf blade—up to 1.5 cm wide (Fig. 8b);

c) small leaves—less than 1.5 cm wide and 5 cm long (Fig. 7).

Articulate-stemmed plants (horsetails). Like cordaites, they occur in almost all lithological varieties. For the most part, longitudinally ribbed stems of these plants, intersected by nodes, are preserved; the long, narrow leaves gathered in rosettes are preserved more rarely. Depending on the width of the stem and the coarseness of the ribs, the following are distinguished:

Fig. 7. Small leaves of cordaites; veins almost parallel, densely arranged

Fig. 8. Cordaite leaves with a broad (a) and narrow (b) leaf blade. Venation is the same as in Fig. 7.

1. Broad (more than 1.5 cm) stems with sharp, coarse ribs (Fig. 9b), which are usually assigned to the genus Paracalamites.

2. Broad (up to 2 cm) or narrow (less than 1.5 cm) stems without coarse ribs, with longitudinal wrinkles or (in the case of a narrow stem) with fine ribs; such forms are assigned to the genera Phyllotheca and Koretrophyllites (Fig. 9a).

In addition, among the plants of the Ilyinskaya and Erunakovskaya formations there are forms that have a restricted vertical distribution. Thus, for the lower horizons of the Erunakovskaya Formation, a very characteristic …

form called Polyssaievia spinulifolia (Fig. 10). It is fairly easy to recognize, and its presence should be noted; the characteristic features of this plant are clearly visible in Fig. 10.

Description of Core

The basic condition for a correct understanding of the character and quantitative distribution of organic remains in the deposits of a section studied from boreholes is the careful examination of the core, with its obligatory splitting along the bedding planes. The quantity of organic remains, the degree of their preservation and the nature of their preservation, and to some extent also their composition, depend on the lithological characteristics of the rocks enclosing them. Below we give the most common cases of occurrence of organic remains, depending on the lithological characteristics of the rocks.

Fig. 9. Articulated-stemmed (horsetail-like) plants. With a narrow stem, thin ribs, and narrow, long, unfused leaves (a). Broad stems with coarse ribs (b).

1. Flora. Plant remains may be present:

a) in the form of a large number of fragments of leaves of cordaites, stems of horsetails, and fern leaves. All these plant remains are arranged in an extremely disorderly fashion, at various angles to the bedding plane. This character of burial is often observed in coarse aleurolites (almost sandstones) and aleurolites.

Fig. 10. Several branches of Polyssaievia spinulifolia.

In this case it is necessary to note the stratigraphic position of all beds in which fragments of fern leaves have been encountered, and for

for cordaites, indicate, in addition, the dimensions of their leaves, at least from fragments (large or small, broad or narrow);

b) in the form of bedding-plane accumulations in very fine-grained sandstones with fine, discontinuous-wavy lamination. The leaves are usually very well preserved or show only faint traces of transport. Bedding-plane accumulations of leaves are also observed in siltstones. In this case they are likewise arranged along the bedding plane, which is usually horizontal. Sometimes the leaves are so numerous that they form a so-called “forest litter” or “mat.” In such cases it is necessary to indicate the size and character of the leaves (narrow large, broad large, small, etc.), whether the composition of the leaves forming the accumulation is uniform or not, and, if not, which of them predominate.

In coarse siltstones, similar accumulations of cordaite leaves are also observed, as well as accumulations of coarsely ribbed horsetails.

In addition to such accumulations of plant remains, isolated impressions are also encountered and should likewise be noted. Isolated impressions of cordaite leaves in excellent preservation occur in thin gray siltstones and in very fine-grained sandstones. In coarse siltstones and very fine-grained sandstones, impressions of ferns are also observed. In these rocks, other parts of plants and representatives of other groups of the Kolchugino flora are often found as well. In the case of such burial of flora, it is necessary to note the size of the cordaite leaves, their number, and the number of fern impressions. Such occurrences are very favorable for specific determinations of the flora; therefore it is desirable that parts of the section composed of the indicated rocks be examined most carefully, with obligatory collection of samples for further detailed paleontological studies.

There is one more type of floral burial. These are isolated, very small, sometimes indeterminable fragments of plants, often only narrow stems of articulate-stemmed plants, or fragments of their narrow, long leaves. This type of flora is characteristic of gray, coarse, non-laminated siltstones and should be noted when describing the core.

It is necessary, when describing the core, also to note intervals completely devoid of plant remains.

2. Fauna is usually present in gray siltstones or thin siltstones without lamination or with banding. Therefore intervals composed of such rocks must be examined carefully. In other lithological varieties fauna occurs much more rarely; however, it may be found in rocks consisting of thin alternation of siltstones and sandstones (Palaeanodonta) and in coarse siltstones (Microdontella).

On p. 341 it was indicated that, depending on the size of shells, their total number, and species composition, the fauna of the Ilyinskaya and Erunakovskaya formations may be divided into three types. In order to form an idea of the general appearance of the fauna and to determine which type of fauna is present in a given stratigraphic interval, the following must be taken into account:

1. The number of faunal impressions on the bedding plane in the core (numerous impressions, isolated impressions, a single impression).

2. The character of the faunal composition—whether the generic composition is uniform or heterogeneous (only microdontellids, only anthraconautids, or both and others, etc.).

3. The size of shells: large (up to 3 cm), of normal size (1.5 cm), small (less than 1 cm).

1. Preservation of the fauna: good, poor (shells badly crumpled, crushed, incomplete shells), and, finally, indeterminate shell fragments.

Accumulations of numerous shell fragments should be noted separately.

Along with these observations, which make it possible to judge the general character of the fauna, it is necessary (as in describing the flora) to select well-preserved specimens for subsequent determination of the species composition.

The considerably more attentive attitude toward organic remains required by the present instructions will increase the quantity and quality of the paleontological material selected for detailed determinations. This, in turn, will provide additional material for solving practical stratigraphic problems, namely: it will make it possible to characterize in greater detail the previously distinguished faunal and phytostratigraphic horizons, to determine precisely the stratigraphic position of the deposits under study, to refine the boundaries of distribution of individual species, to reveal features in the distribution of flora, fauna, etc.

Correlation of Sections

The purpose of the present instructions is to draw the attention of workers of geological-exploration parties to the enormous paleontological material that is extracted daily in the cores of boreholes, and to turn it into an additional criterion in correlating sections in the everyday work of geological-exploration parties. For this it is necessary that all observations on the character of organic remains that can be made under field conditions (in accordance with the provisions set out above) be reflected when drawing lithological columns for boreholes.

These observations are recorded in the form of a table, the vertical columns of which correspond to the following groups of organic remains:

1. Cordaites: a) large leaves; b) narrow long leaves; c) small leaves.
2. Horsetails: a) with a broad stem; b) with a narrow stem.
3. Ferns: a) genus Pecopteris; b) genus Callipteris.
4. Genus Glottophyllum.
5. Genus Polysaievia.
6. Pelecypods: a) genus Palaeanodonta; b) genus Anthraconauta; c) genus Microdontella; d) rare shell fragments; e) shell detritus.
7. Ostracods.

To the left of the table is placed the lithological column of the given borehole (instead of a lithological column one may limit oneself merely to indicating the coal seams in the section of the given borehole).

In the vertical columns of the table, opposite the corresponding meter of depth, the presence of the organic remains found is marked with crosses:

+++ a large number of impressions (many leaves of cordaites, ferns, shells, etc.).

++ few impressions.

• single impressions.

The data obtained in this way make it possible to outline horizons characteristic in the composition of flora and fauna, which can be used for correlating the sections being compared.

Figure 11 shows the distribution of fauna and flora in the core of borehole 323 of the Tagarysh deposit. In this borehole three horizons are clearly distinguished:

a) the lower horizon (below seam 15) is characterized by abundant and varied fauna and an almost complete absence of flora;

b) the middle horizon (from seam 15 to seam 22), conversely, contains fairly varied flora and is entirely devoid of fauna;

c) the upper horizon (above seam 22) is distinguished by the joint occurrence of flora and fauna, although both are more uniform and scanty than in the lower horizon.

Fig. 11.                      Fig. 12.

If we now compare the section of borehole 323 with the section of borehole 335 of the same deposit (Fig. 12), we shall be convinced, from the character of the organic remains, that in borehole 335 almost the entire section belongs only to the lower horizon, which in this borehole has a greater thickness than in borehole 323, since it is opened more completely.

The most favorable case for applying this method is, of course, when remains of both fauna and flora occur in abundance in the section of a deposit; in this case there are more initial data for clarifying the paleontological characteristics of the horizons and determining the position of the boundaries between them. But in some districts (for example, in the deposits of the Prisalaír belt of Kuzbass) fauna is almost absent in the deposits of the Kolchuginskaya series. Let us consider

this more difficult case, using as an example the section along exploration line VIII of the Babanakovsky III area of the Belovskoye deposit.

Let us begin the analysis with the eastern limb of the Babanakovskaya anticline; here material is available from three boreholes.

Fig. 13.

Fig. 14.

In borehole 233 (Fig. 13) the flora is fairly uniform through almost the entire section, and only in its lower part, from a depth of approximately 162 m, are certain changes observed:

a) cordaites with small leaves disappear, whereas higher in the section they predominate; b) horsetails with broad stems disappear.

Thus, at a depth of 150 m¹ a certain change in the character and composition of the flora is indicated.

In the neighboring borehole No. 234 (Fig. 14), to the SE, the change in the character of the flora occurs somewhat earlier (depth 130 m) and has the same character. In addition, however, representatives of the genus Glottophyllum appear here in the lower horizons. Thus, already on the basis of these two boreholes it becomes possible to distinguish two horizons: horizon I (upper), characterized by the predominance of cordaites with small leaves and by the presence of horsetails with broad stems; horizon II (lower), characterized by the predominance of cordaites with broad leaves, the predominance of horsetails with narrow stems, and the presence of representatives of the genus Glottophyllum.

In the deposits of both boreholes the fauna is extremely scanty; however, if in horizon I large microdontellids are present, albeit rarely, then in horizon II there is no fauna at all.

Further to the southeast, in borehole 229 (Fig. 15), the same regularity again appears: down to a depth of 78 m in the section, small leaves of cordaites are widely developed, while below this, cordaites with broad leaves sharply predominate; below this boundary representatives of the genus Glottophyllum again appear and become widespread, the number of horsetails with narrow stems increases markedly (with a sharp reduction in horsetails with broad stems), and, in addition, a very large number of ferns of Pecopteris appears. Thus, in this borehole the two floristic horizons already distinguished by us (I and II) are repeated, and the boundary between them lies at a depth of 78 m.

On the southeastern limb of the anticline, in borehole 232 (Fig. 16), the composition and character of the flora are somewhat different. Here the deposits of horizon I, characterized by the predominance of small-leaved cordaites and broad-stemmed horsetails, are absent. By the predominance of cordaites with broad leaves, horsetails with thin stems, and by the presence of the genus Glottophyllum, we recognize in this borehole deposits of horizon II. But at a depth of 160 m in this borehole a new change is outlined in the composition of the organic remains: the number of cordaites in general decreases, Polysajewia spinulifolia appears, ostracods appear, and pelecypods, which in horizons I and II were encountered extremely rarely, are here sufficiently abundant, although monotonous. On the basis of these changes it seems possible to distinguish, below 160 m, horizon III (the lowermost).

Thus, in the deposits opened by the listed boreholes of exploration line VII, three horizons can be distinguished on the basis of the features in the distribution of the flora and partly of the fauna. These horizons are distinguished by means of conventional symbols and serve as the basis for tying together the sections in the boreholes of this exploration line (Fig. 17). In an analogous manner, sections along neighboring lines and within the area as a whole are tied together.

The next step in the use of paleontological material for purposes of stratigraphic correlation is the compilation of a summary table-diagram of the distribution of organic remains for the entire area or deposit. In such a table it is already necessary to take account of individual species as well, which requires careful selection of samples of good preservation. On the basis of the summary table-diagram, faunistic and phytostratigraphic horizons receive a more complete characterization, their boundaries are refined, and, at the same time, the effectiveness of the use of paleontological material is increased not only for the day-to-day work of geological exploration parties, but also for broader constructions.

In conclusion, it is necessary to dwell on one phenomenon that occurs in the distribution of the pelecypod fauna in the sections of a number of deposits. This phenomenon is called recurrence and consists of the repeated appearance in a section of a certain association of organic remains. Thus, in the section of the Uskatskoye deposit a horizon with a depressed fauna is repeated twice; the same phenomenon is observed in the deposits of the Leninskoye deposit. This circumstance must be taken into account when correlating sections from individual boreholes in order to avoid errors. Data on the fauna must be supplemented by observations on the character of the flora. Thus, in the above-named deposits, the flora of horizons containing the same fauna proved to be different. In the Uskatskoye deposit, horizon I (the first horizon with a depressed fauna) is characterized by a generally scanty flora, but with a rather large number of ferns—

Fig. 15.

Fig. 16.

…whereas for horizon IV (the second horizon, with a similarly impoverished fauna) a broad development of cordaites and an almost complete absence of ferns are characteristic.

It must also be borne in mind that it is not always possible, from a single borehole, to outline the boundaries of the horizons with sufficient precision and to establish their paleontological characteristics; for this a certain sum of observations is needed, obtained by comparing data from several boreholes.

The method characterized above has been tested at a number of deposits; after some practice, it makes it possible, without great effort and with a minimal expenditure of time, to use organic remains—abundantly encountered in the deposits of the Ilyinskaya and Erunakovskaya formations—for correlating sections and, consequently, coal seams.

Conclusion

The present instruction contains the minimum knowledge of the paleontology of the Kolchugino Series necessary so that geological-exploration parties can already now use organic remains in their everyday work. This should lead to improvement and refinement of the stratigraphic constructions made by the parties in the course of their work; in other words, it will contribute to a more successful solution by the parties of the tasks confronting them. But at the same time this will impart…

primary documentation and party reports to a higher level and will entail the accumulation of materials for solving a broader and very complex problem: that of elucidating the regularities of facies changes in the deposits of the Kolchugino Series, without which reliable stratigraphic correlation of sections of this series on the scale of the basin is impossible. This is especially important because the core material obtained by parties in enormous quantities cannot be preserved for a long time, and there is no possibility of organizing its paleontological description other than by the efforts of the parties themselves in the course of exploration of the deposit.

VIII exploration line

Paleontological horizons: I; II; III

Fig. 17.

The application of the present instruction should be regarded as the first step toward introducing the paleontological method into the practice of geological-exploration parties in Kuzbass. After the methodology proposed in this instruction has been mastered by the appropriate personnel of the parties, it will become possible to take the next step toward a broader use of paleontological material; if, in parallel, the lithological description of the core is also improved, all this taken together will constitute a merging of the production work of the parties with scientific work.

It may be expected that even the application of the present instruction will increase the interest of party workers in paleontological material. In order to foster the possible emergence of the corresponding initiative, it would be useful for the parties to have the principal summaries on the fauna and flora of the coal-bearing deposits of Kuzbass that have been published recently. Further, measures should be taken to ensure that the parties are supplied with those identification guides, handbooks, and atlases that relate to the paleontology of Kuzbass and that have already been published or are to be published in the near future.

Tomsk Polytechnic Institute
named after S. M. Kirov

1. We note that the boundaries between adjacent horizons always represent a certain bed of small thickness (several meters), in which the organic remains have a mixed character; in the present case the boundary between horizons I and II corresponds to an interval about 8 m thick (between depths of 152–160 m). ↩